Twist off tamper-proof fastener

Abstract

A twist off tamper-proof fastener having an elongate flexible strap defining a plurality of parallel adjacent transverse teeth in opposing planar surfaces. First end portion of elongate strap is tapered to a rounded tip for insertion through a “T” slot defined in a dimensionally larger head portion carried at opposing end of the elongate strap. A fixed tooth and plural angulated teeth carried by a flexing arm irremovably engage with the teeth defined in the elongate strap. The head portion is elliptic with opposing spaced apart rounded ends and opposing planar sides to facilitate grasping and twisting by a user, and for identifying indicia. A circumferentially extending notch is defined in the elongate strap immediately adjacent the head portion. Twisting the head portion creates shearing forces that are focused at the circumferential notch breaking the fastener and allowing removal without tools.

Description

RELATED APPLICATIONSThere are no other patent applications related hereto heretofore filed in the United States of America or in any other country.BACKGROUND OF INVENTION1. Field of InventionThis invention relates to clasps and closures and more particularly to single use fasteners having a head portion defining a slot at one end of an elongate strap that loops over and irremovably engages in the slot.2. Background and Description of Prior ArtFasteners of the instant type are commonly referred to as “cable ties” and are well-known for fastening items together such as container latches, bundles of wire and groupings of flexible tubular members. Typically the fastener is threaded through adjacent aligned holes defined in portions of a container that move distally from one another when the container is opened, or the fastener is extended circumferentially around the bundle of wires / groupings of hose to secure the wires / hoses in proximity to one another.Generally, cable ties have an elo...

AI Technical Summary

Benefits of technology

A twist-off tamper-proof fastener having an elongate flexible strap defining a plurality of parallel adjacent transverse teeth in opposing planar surfaces. First end portion of elongate strap is tapered to a rounded tip for insertion through a “T” slot defined in a head portion carried at opposing end of the elongate strap. A fixed tooth and plural angulated teeth carried by a flexing arm irremovably engage with the teeth defined in the elongate strap. The head portion is elliptic with opposing spaced apart rounded ends and opposing planar sides to facilitate grasping and twisting by a user, and for identifying indicia. A circumferentially extending notch is defined in the elongate strap immediately adjacent the head portion. Twisting the head portion focuses shearing forces at the circumferential notch breaking the cable tie and allowing removal without tools.

a further object to provide a twist off tamper-proof fastener having a peripheral frame around the “T” slot that prevents tampering with the arm.

a still further object to provide a twist off tamper-proof fastener that is of new and novel design, of rugged and durable nature, of simple and economic manufacture and one that is otherwise well suited to the uses and purposes for which it is intended.

Problems solved by technology

Once the elongate strap is inserted through the slot and the pawl has engaged with the parallel transverse grooves, the elongate strap cannot be withdrawn from the slot without breaking the pawl, breaking the elongate strap or otherwise physically destroying the cable tie.

Once the cable tie has been broken, it cannot be repaired or re-affixed.

The inability to remove a fastened cable tie without physically or functionally destroying the cable tie is both a desirable feature and a drawback.

Conversely, if the container or the cable tie have been broken, it can reasonably be assumed that the original contents of the container have been tampered with and are no longer in the condition and perhaps quantity, as they were when the cable tie was originally secured to the container.

By the same token, one of the drawbacks of cable ties is that they are difficult to break.

Cutting the cable tie with a wire cutter or knife poses a risk of unintentionally damaging the item being secured and requires use of a tool.

Breaking the cable tie by inserting an elongate rigid object, such as a screwdriver, through the looped elongate strap and twisting the object to break the cable tie is even more likely to damage the item secured by the cable tie.

Unfortunately, shearing forces such as those used to intentionally break known “tear away” cable ties may be inadvertently applied to the cable tie if the rectilinear tag is inadvertently caught between two surfaces that move relative to one another, such as a top and a bottom or adjacent sides of adjacent containers being transported in a vehicle.

Further, known “tear away” cable ties with rectilinear tags have sharp edges and corners, they are not aesthetically pleasing, they are difficult to package in bundles because the rectilinear tags “catch” on one another and they can be difficult to manufacturer.

When broken, the fact the cable tie has been broken is un-mistakenly identifiable.

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